PROJECT SUMMARY Childhood obesity is a formidable public health issue in the United States, disproportionately affecting children from lower socioeconomic status households. Onset of obesity predicts cardiometabolic risks and other health problems in adolescence and into adulthood; thus, effective and early prevention is critical. Healthy parenting may play a pivotal role in preventing early childhood obesity. Warm, responsive, and consistent parenting is associated with the development of child self-regulation as well as healthy eating and physical activity practices, and thus may be protective against obesity risk. However, few interventions have been successful in changing obesity-related parenting practices, and none have evidenced long-term success in preventing child obesity in low-income children. One reason for the lack of long-term efficacy may be that no prevention programs have focused on improving the parent-child relationship and parent-child interactions. Targeting the parent-child relationship may be especially important when facilitating behavior change in parents who have ongoing stressors (e.g., low-income families). The proposed study aims to test an adaptation of Parent-Child Interaction Therapy (PCIT), an innovative parent management program that improves the parent-child relationship and enhances general parenting skills through the use of therapeutic in vivo coaching. Our adapted version, PCIT-Health, is a selective-prevention intervention that includes content specific to improving parent-child interactions and parenting in obesity-salient contexts, such as mealtime and child screen time. This project will elucidate novel approaches to, and novel targets of, early childhood obesity prevention and will provide data critical for a subsequent R01 application to test PCIT-Health in a large-scale randomized controlled trial. Seventy-five parent-child dyads from low-income households will be randomly assigned to PCIT-Health or a waitlist control in order to accomplish the following aims:.AIM 1: To assess the acceptability and feasibility of the PCIT-Health delivery and assessment methods in low-income parents of overweight young children ages 3 to 6 years. AIM 2: To test the preliminary efficacy and estimate the effect size of PCIT- Health on changes in child BMI z-score (primary outcome) from baseline to (1) intervention completion and (2) 6-month post-intervention. AIM 3: To explore the effect of PCIT-Health on the following secondary outcomes: (1) parent-child relationship quality, (2) parent behavior management skills, (3) child self-regulation, (4) child eating behaviors, (5) child physical activity, and (6) child screen media use.